Manufacture of esters of fatty acids and of mixtures containing fatty acids



Patented May 13, 1930 UNITED STATES ERNST WECKEB, OF HEILBRONN-N-THE NECKAR, GERMANY 4 MANUFACTURE OF ESTERS OF FATTY ACIDS AND OF MIXTURES CONTAINING FATTY ACIDS No Drawing. Applicationfiled June 20, 1927, Serial No. 200,285, and in Germany June 23, 1926.

1 cover the excess of glycerin ina simple mannor from the reaction mass.

In contrast therewith the present process provides a very simple and economical method for the esterification of higher fatty acids containing at least 4 atoms of carbon in the molecule, such for example as occur in vegetable and animal fats and oils and the recovery of 'all the ingredients which have not been esterified, as well as protection for the esterified ingredients. The present process consists in that esterification is carried out with-' out an excess of glycerin, and is only allowed to reach a certain stage, the excess of the fatty acids left in the reaction mixture being removed by a purifying process, in which a suddenly expanding liquid mist is introduced into the heated reaction mixture or by means of neutral gases or superheated vapours which, desired, may act as carriers for the said liquid mist, the said vapours and gases being equivalents for the purposes of the present invention, which is injurious neither to the fatty .acids nor to theneutral oily portions. v

The process is therefore carried out so that fatty acids, 5or neutral oils containin a high 7 percentage of fatty acids, are esterifi ed with an alcohol, preferably glycerin, the quantity of glycerin being so adjusted that it remains below the quantity stoichiometrically required, with the result that while an excess of fatty acid is left all the glycerin present is completely used up in the esterificati'on process. I 4

The resulting reaction mixture containing an excess of fatty acids, is thereupon freed from the said acids in accordance with the process explained above, for example, by heating. it to a high temperature, preferably close to the boilingpoint ofthe fatty acids,

and thereupon treating it finelydivided liquids such as for example water, toluol,

vacuum, for example 10 to 40 mm. of mercury. In place of the finely divided liquid, or in conjunction therewith, superheated vapours or neutral gases, for example hydrogen or the like may be used.

To remove the fatty acids, the reaction mixture to be purified is preferably caused to flow in a relatively thin layer, for example through a washing space subdivided into several single chambers, the conditions being such that the purifying agent remains in contact with the flowing fats or oils for a very short time only, and is then immediately led away with fatty acids and other volatile ingredients.

The excess of fatty acids thus separated may be used afresh in the esterification fying process hereinbefore described wherein liquid mist, neutral gases or superheated vapours are used. Thus, startln from oils or fats containing more or less fatty acids,

process whereafter the fatty acids or mix- I the said oils and fats are purified by the said tures of fatty acids obtained, which do not contain any, neutral oil, or only relatively small quantities thereof, are submitted to an esterification process together with' suchquantities of glycerin or other alcohols as are completely used up in the said process. The excess of fatty acids is then removed from the esterification reaction mixture as hereinbefore described, in order that the said excess may again be subjected to the esterification process if desired.

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Examples 1.10 kg. of 93% fatty acid derived from peanuts and about 7% neutral oil are esterified as known with 0.9 kg. of glycerin. 'At the end of the reaction the reaction mixture still contains 9.5% of free fatty acid. The glycerin is completely consumed, except for traces found in the condenser and which remained therein during several consecutive operations. The acid reaction mixture is treated in a vacuum of 20 mm. at 250 with water mist, the carrier for which is super heated steam. After the rapid separation of the fatty acids 9.38 kg. of neutral oil containing 0. i% of free fatty acid remains, while the 0.58 kg. of fatty acids separated are used for a fresh operation.

2. 10 kg. of sesame Oll fat-tyacid with 95% offree fatty acid and about 5% of neutral oil, are esterified with 0.9 kg. of glycerin, as in Example 1. After the reaction is completed.the reaction mixture still contains 11.42% of free fatty acid whichwas separated (as in Example 1) by superheated steam charged with water mist. The-resulting quantity of 9.18 kg. of neutraloil still contains 0.3% of free fatty acid. The 1.18 kg. of fatty acid separated was utilized in a subsequent operation. The glycerin is completely used up.

The new process has the advantage that it can be carried out to afford the greatest possible protection to the existing or newlyformed neutral oils and fats, and that during each stage of the separation of the fatty acids practically colourless and high percentage products are obtained, the renewed esterification of which with glycerin can readily be effected quantitatively. The difficult operation of recovering any glycerin not used up in the reaction, is rendered superfluous and losses of neutral oil are likewise avoided. The utilization of the fatty acids of valuable oils, for example sesame oil, peanut oil, etc.,

for the manufacture of food is made possible in a simple and economical manner by the present process of esterification.

Wide modifications can be made in the present process either as regards the particular form of the esterification process or the .physical washing-out methods used therewith, as well as in respect of the construction of the apparatus used, or the continuous or non-continuous method of treatment and the sequence of the various stages of the treatment, etc.

I claim:

1. A process for the esterification of higher fatty acids containing at least four atoms of carbon in the molecule which consists in treating the said fatty acids with less than the corresponding stoichiometric quantity of alcohols, whereupon the excess of fatty acids is removed by introducing a suddenly exany of the components of the reaction into the heated reaction mixture.

2. A process for the esterification of higher fatty acids containing at least four atoms of carbon in the molecule which consists in treating the said fatty acids with less 3. A process for the esterification of higher I fatty acids containing at least four atoms of carbon in the molecule which consists in treating the said fatty acids with less than the corresponding stoichiometric quantity of alcohols, whereupon the excess of fatty acids is removed by introducing a suddenly expanding liquid mist which is not injurious to any of the components of the reaction into the heated reaction mixture at a pressure of less than 40 millimeters of mercury.

4;. A process for the esterification of higher fatty acids containing at least four atoms of carbon in the molecule which consists in treating the said fatty acids with less than the corresponding stoichiometric quantity of alcohols, whereupon the excess of fatty acids is removed by introducing a suddenly expanding liquid mist which is not injurious to any of the components of the reaction into the heated reaction mixture in the presence of a neutral gas acting as a carrier for the said mist.

5. A process for the esterification of higher to any of the components of the reaction into the heated reaction mixture in the presence of a neutral gas acting as carrier for the said mist and under reduced pressure.

6. A p'rogess for the esterification of higher fatty acids containing at least four atoms of carbon in the molecule which consists in treating the-said fatty acids with less than the corresponding stoichiometric quantity of alcohols, whereupon the excess of fatty acids is removed by introducing a suddenly expanding liquid mist whigh is not injurious to any of the components of the reaction into the reaction mixture heated close to the boiling point of the fatty acid. l;

7. A process for the esterification of higher fatty acids containing at least-four atoms of carbon in the molecule which consists in treating the said fatty acids with less than the corresponding stolchiometric quantity of 65 panding liquid mist which is not injurious to glycerin, whereupon the excess of fatty acids too is removed by introducing a suddenly expanding liquid mist which isnot injurious to any of the components of the reaction into the heated reaction mixture.

8. A process for the esterification of higher fatty acids containing atleast four atoms of carbon in the molecule which consists in treating the said fatty acids with less than the corresponding stoichiometrie quantity of glycerin, whereupon the excess of a fatty acids is removed by introducing water mist into the heated reaction mixture in the presence of superheated steam acting as carrier for the said mist at a pressure of 20 millimeters of mercury.

In testimony whereof I afiix my signature. ERNST WEOKER. a 

